1. Field of the Invention
This invention relates to a speakerphone, more specifically to novel way of placing loudspeakers in a speakerphone to improve the intelligibility of speech of conference talker.
2. Description of the Related Art
Teleconferencing has long been an essential tool for communication in business, government and educational institutions. There are many types of teleconferencing equipment based on many characterizations. One type of teleconferencing unit is a video conference unit 100 as shown in FIG. 1, which transmits real-time video images as well as real-time audio signals. A video conferencing unit 100 typically comprises a video processing component and an audio processing component. The video processing component may include a camera 102 to pick up live images of conference participants and a video display 130 for showing real-time video images of conference participants or images of documents. The audio portion of the video conferencing unit 100 typically includes one or more microphones 145 and 155 connected to a processor 110 through wires 156 and 157 to pick up voice signals of conference participants, and loudspeakers 122 and 124 to reproduce voices of the participants at the far end. The processor 110 is connected to the far side of the conference through a cable 150. The processor 110 may control the operation of the video conference unit 100 and perform any the data processing necessary during operation.
Another type of teleconference unit is an audio conference unit, which is typically a speakerphone or a simple telephone that includes at least a loudspeaker and a microphone. FIGS. 2a-2c illustrate a few examples of speakerphones. A speakerphone can be viewed as essentially a video conference unit without the video capability and the video-related hardware and network supporting infrastructure. To make an audio-only conference call using a speakerphone is much simpler and easier than using a videoconference unit. A speakerphone is typically much cheaper than a videoconference unit. An analog telephone is typically the cheapest, simplest and easiest to use teleconference unit.
FIG. 2a shows a typical speakerphone 200, for example, a Polycom VTX-1000 speakerphone which is commercially available from the assignee of the current patent application. The speakerphone 200 has several microphones 242, 244 and 246, a loudspeaker 222 and a control module 260. The control module 260 has a controller (not shown) that is coupled to the loudspeakers, microphones and network interface (not shown). The control module also has two keyboards 270 and 272 and a display screen 262. A cable 250 coupled to the network interface (not shown) provides power and network connections. FIGS. 2b and 2c show a slightly different speakerphone 210, which has similar components including microphones 212, 214 and 216, loudspeaker 222 and a control module 220. In speakerphone 210, the components are arranged in a slightly different physical configuration compared to the speakerphone 200. FIG. 2b shows a top view and FIG. 2c shows a side view of the speakerphone 210.
The low cost of a speakerphone is often associated with the low audio quality of the speakerphone. It is common that when several people participate in a conference call, it may be difficult to understand what a talker on the far end is talking about even if the volume of the speakerphone is turned on high. The conference call participants at the near end may have to sit very close to the speakerphone to be able to hear and understand the far end talker. This makes the participants to crowd over the speakerphone, even though there is plenty of space in the conference room. This makes the conference very uncomfortable and inconvenient.
The problem associated with the difficulty of understanding the talkers at a far end site when there are several people on both conference sites does not appear to be solved by turning up the volume on the speakerphone. Such problem does not appear to be present in many video conference units, which are substantially more expensive.
It is desirable to have a method and a speakerphone with improved sound quality without incurring the substantial cost of a videoconference unit.